Method and means for the removal



Aug. 7, 1951 A. w. DANIELS 2,563,517 METHOD AND MEANS FOR THE REMOVALAND TRANSPORT OF ASHES AND THE LIKE FURNACE RESIDUES Filed Dec. 16, 19464 Sheets-Sheet l (in Attorneys 1951 A. w. DANIELS 2,563,517

METHOD AND MEANS FOR THE REMOVAL AND TRANSPORT OF ASHES AND THE LIKEFURNACE RESIDUES Filed Dec. 16, 1946 4 Sheets-Sheet 2 M 241 1;, Mill? 13I Aug. 7, 1951 A. w. DANIELS 2,563,517

METHOD AND MEANS FOR THE REMOVAL AND TRANSPORT OF ASHES AND THE LIKEFURNACE RESIDUES Filed Dec. 16, 1946 4 Sheets-Sheet 3 @Allurneyj A g-1951 A. w. DANIELS 2,563,517

METHOD AND MEANS FOR THE REMOVAL AND TRANSPORT OF ASHES AND THE LIKE!FURNACE RESIDUES Filed Dec. 16, 1946 4 Sheets-Sheet 4 Inventor PatentedAug. 7, 1951 METHOD AND MEANS FOR EMOVAL D Ta sroR'r or ASHES AND THELIKE FURNACE RESIDUES" Arthur Wylde Daniels, London, England, assignorto B. V. 0. Industrial Constructions Limited, London, England, a Britishcompany Application December 16, 1946, Serial No. 716,644

In Great Britain May 27, 1946 16 Claims. A 1

This invention relates to a new or improved method of and means for theremoval and transport of ash and the like furnace residues that findsparticular application, though without limitation, to the removal of ashand clinker and like residues from fuel burning furnace and inparticular the ash pertinent to pulverise'd fuel fired boilers.

Hydraulic sluicing for breaking down and removing compacted particles ofmatter is Well known both for removal of furnace ash and miningconglomerates and kindred earth strata that are water permeable, thesolid matter eroded by sluicing bein conducted by aqueous entrainmentfor treatment in sluiceways or fiumes, the solid matter being eparatedfrom its entraining water by known means at any desired point.

The single jet normally employed is adapted to react upon a single planeand have an area of clearance that is proportional to the energy of thejet, and since the really effective length of jet projection witheconomic pressure is at a maximum at about ten feet, it has heretoforebeen arranged that the ash hopper base has been divided into a series ofrelatively short individual sloping ash hearth planes so that eachsingle jet has its own appropriate area for ash removal, the backwashclearing the ash away for entrainment.

It has also been devised that a hopper base or ash hearth has had aseries of jets positioned transversely of its length, and the jetsarranged to oscillate about a central entry. In this latter case theeroding cross or diagonal stream interferes with the entrained flow ofash to the outlet, and in some positions of the jet during oscillationthe eroding stream is angularly against the escaping flow. This featureleads to ash piling and the creating of ash deposits between the jetentrances or centres.

Again if a long ash hopper base is divided into multi-hearths with theattendant multi-fittings and pertinent jets there is a high capitalcost, and a high maintenance cost. Such arrangement of hearthsinevitably entails an unduly long and involved ash removal operation indealing separately with each hearth and the hand manipulation of eachjet and its pressure water supply.

Again in many forms of jet cleared ash hopper bases a haunch plate isused to divide the hopper base into convenient compartments each forindividual and separate ash clearance. If the refractory haunchingsbetween adjoining hearths are built in the form of a triangular prism itis well known that the radiant heat from the furnace very soon destroysthem, whilst it in order A to overcome this difficulty the haunchingsare made fiat topped, then these fiat upper faces of the haunch roofingform a source of lodgement for ash beyond the-effective reach of thejet, and the layers of ash thu brought nearer to the heat source of fuelcombustion tend to vitrify and form a glazed layer requiring periodicremoval by hand, which may compel a shut down.

Thus a further object of the present invention is to totallyavoidhaunching and utilise a continuous base Whose'length may be of anydimensions that is convenient to suit the width of the boiler furnace.The above feature is in line with the modern tendency to very greatlyincrease the evaporative capacity of individual steam producing unitsand the ash hoppers for such purpose become of dimensions wherein thedifficulty of ash removal over sectional areas is increased.

A further difflculty arises with short length ash hearths and singlejets in that the said ash may avalanche and chokeithe exitand the mainconveying sluiceway. In normal practice the exit to any hearth isguarded by a counterweighted hinged flap door, so that when ashavalanching takes place, the impact of the ash mass overcomes thecounterpoise, and enables some of the avalanching ash to choke the exitand the main conveying sluiceway. A A

Apart from the above objectives the invention seeks to remove in aneconomic manner many of the difficultie that have existed heretofore, tosimplify the necessary ash hopper construction below the grate orfurnace and provided a method that can be flexibly employed at will forremoving varying grades and composition of ash and scoria, and whereinthe actuating means for such removal are automatically or otherwiseplaced in an operative position and then automatically or otherwiseremoved from the path of ash entrainment. A

According to the invention a method of displacing and removing ash orother solid material is provided which consists in compelling said solidmaterial to accumulate in a pile on a support upwardly inclined fromfront to rear, progressively erodin and disintegrating said pilebyprojecting against the front surface thereof, in sequence from front torear of said support as the front surface of said pile recedes, a seriesof high pressure hydraulic jets directed upwardly along said support andlocated therealong in tandem at intervals not greater than the effectiveoperating length of said jets, and in assisting the aqueous entrainmentand removal of said eroded or disintegrated solid material down and awayfrom said inclined support by projecting down said support, in sequencewith said first series of jets, a further series of hydraulic highpressure jets arranged in tandem therealong.

According to a further feature of the invention means are provided forcooling said support. The method of displacing and removing ash or othersolid material according to the inven-i tion also provides for theoperation of a down-,

wardly directed jet or jets alternately with an.

upwardly directed jet or jets and for the arrangement of said jets so asto operate over separate zones collectively extending over the entirewidth of the front face of said pile.

The invention also provides for carrying into effect the methoddescribed above in the displacement and removal of furnace ash,apparatus wherein a single trough shaped ash receiving hopper of greaterlength than breadth is formed with sides converging towards alongitudinally linclined base having a positively operated gatecontrolled frontal exit at the lower end thereof and. arranged in tandemlengthwise along said base, a series of rearwardly directed and a seriesof forwardly directed jet assemblies, adapted to the minimum impedanceto the movement of the 4 entrained solids towards the exit from thehopper base.

- Preferably the said control gate is of an arcuate type that isself-clearing and pivoted about a shaft transverse of the said exit,said gate being counterpoised and mobile under hand or electricalsolenoid control. Said gate is provided with such grooving on itsclosure edge as will admit drainage from the hearth or base in itsclosed condition.

a The base or hearth of the hopper is preferably of metallicconstruction, and the jet assemblies are disposed along said base, eachupon separate pivoted mountings, one surface of said mounting being flatand presented to be level with the base '-when the jet assembly isinoperative, whereby uninterrupted flow can take place above saidmounting when the jet assembly is retracted. This method of mounting isor may be applied to all jet assemblies excepting the frontal jetassembly, but said assemblies are stream lined in the direction of ashflow when in the operative position so that the minimum of impedance ispresented to the fluid stream.

According to the preferred form the jet assemblies are automaticallypositioned for operative use in the hearth by admitting fluid underpressure to the jet assemblies and said jet assemblies are automaticallyretracted on the cessation of pressure fluid supply. Such automaticmovement and operation of the jet assemblies is accomplished in one ormore of several ways, i. e. by the reactive force of the pressure fluidsupply,

:by hydraulic means with a hydraulic cylinder and piston or by linkmotion from a prime mover actuated by fluid pressure or an externalsource of power. Retraction of said jet assemblies may 'be assisted tothe limit of movement by resilient or gravitational means.

-' The base of the ash hopper is preferably formed of cast ironsectional blocks which are arranged to provide an even upper surface andare interlocking. These sectional blocks are preferably hollow andcooledby circulating water, the series resting upon a concrete bed, orupon cross bearers. The base or hearth is formed to approximate a.semi-circular sectioned trough, and slopes from the back to the frontand the jet assemblies are arranged to penetrate the hearth floor orreplace one or more of the cast iron blocks, the gear for retracting thejet assemblies being mounted preferably below said hearth.

To accelerate the operation of ash removal it is important that thefunctions of the operator are reduced to the simplest possible terms andaccording to the invention the various functional units of apparatus maybe electrically controlled from a single panel by push button or microswitch initiating devices or alternatively by remote hydraulic controlwherein the master control, levers are grouped together and as in theThese controls are jet assembly also causes said jet assembly to beoperatively positioned, and. in some cases the cessation of supplyretracts same.

Throughout the specification the term jet is used to indicate the jet ofwater and the term .1 jet assembly includes the nozzle and the housingin which it is arranged.

= I Reference will now be made to the accompany- ..ing drawings whichillustrate preferred forms of construction of the ash hopper andretractable jet assemblies provided therein according to the .invention,and in which:

Fig. 1 is a plan view of the hopper, Fig. 2 is a sectional elevation onthe line II-II Fig. 3 is a section on the line III-III of Fig. 2,

- Fig. 4 shows a part sectional side view of one form of construction ofa retractable jet assembly arranged in the hopper base,

Fig. 5 is a cross-sectional view through the base of the hopper providedwith the retractable jet assembly shown in Fig. 4,

Fig. 6 is a section through the gate controlled outlet of the hopper inthe open position thereof, on the line VI-VI of Fig. 2,

Fig. 7 is a view on the line VII-V1I of Fig. 2, with the gate in theclosed position,

Fig. 8 shows a sectional plan of another form of construction of aretractable jet assembly arranged in a side wall of the hopper,

Fig. 9 is a sectional plan View of the hopper with the jet assemblyshown in Fig. 8 provided in the side walls thereof,

. Fig. 10 is a rear elevation of the jet assembly shown in Fig. 9,

Fig. 11 shows a front elevation of another form of construction of aretractable jet assembly,

Fig. 12 is a longitudinal section of the je assembly shown in Fig. 11,

Fig. 13 shows the application of automatic means for retracting the jetassembly shown in Figs. 11 and 12, and

Figs. 14 and 15 show in side elevation and plan respectively, details ofa streamlined retractable jet assembly. I

The hopper is of trough shape and formed with downwardly converging sidewalls 2 and frontand re'ar walls 3 and 4 terminating in a base orhearth-5.. The walls of the hopper are all lined with refractorymaterial 6 such as firebrick or the like and are supported by metalframe members I mounted on a bed 8 of concrete or other suitablefoundation. The lower portion of the refractory lining 6 has a metalfacing 9 and the base 5 of the hopper is formed of interlocking metalsectional blocks l resting on a metal support ll carried by the framemembers I. The blocks 10 are formed underneath with intercommunicatingchannels l2 to provide a labyrinthine passage thereunder for coolingwater from supply pipe 64 in the rear wall 4, the cooling of the blocksl0 assisting the prevention of vitreous particles of ash agglomeratingand adhering to the blocks l0. As shown in Fig. 2, the base of thehopper I is formed with a downward inclination from the rear wall 4 tothe front wall thereof and terminates in an outlet 13 closed by apivotally mounted arcuate gate 14 provided with counter balance weightsl5 and a handle l6 for the operation thereof. The outlet I3 and gate I4are enclosed in a casing l1 enabling the entry of air to the base of thehopper to be prevented or controlled, and the arcuate gate 14 is groovedso as to permit drainage of liquid from the base 5 when the gate isclosed. In the wall of the casing ll facing the outlet I3 is a highpressure hydraulic jet assembly 18 directed towards the outlet l3.

Below the outlet I3 is a sluiceway l9 provided with one or more jetassemblies for assisting the entrainment and removal of the materialdelivered thereto from the hopper outlet [3.

Arranged in tandem at intervals along the base 5 of the hopper l are twoseries of pivoting jet assemblies 18, the nozzles 20 of one series beingadapted to operate upwardly along the said base 5 and the nozzles 28 ofthe other series being adapted to operate downwardly along the base 5.These jet assemblies la in the hopper base are arranged so that wheninoperative they present towards the interior of the hopper l a surfaceflush with the blocks H]. Details of the construction and arrangement ofthe hopper base jet assemblies 18 are shown in Figs. 4 and 5.

Each jet assembly consists of a jet housing 2| fast on a hollow shaft 22and formed with an integral curved conduit 23 one end of which is incommunication, within the housing 2!, with the hollow shaft 22, and theother end of which is threaded to receive the threaded nozzle 24.

The exterior of the conduit 23 is streamlined to present the minimumimpedance to fluid flow. The jet housing 2| is in side view shapedapproximately as an equilateral triangle the corners r 25 of the housing2| being truncated and formed with a curved contour forming an arc of acircle the centre of which is coincident with that of the said triangle.At two of said truncated corners stops 26 are provided so as to limitrotation of said housing 2| to 120. The hollow shaft 22 is perforated tocommunicate with the conduit 23 and is pivotally mounted at either endin bearings 2i fixed in the frame members 1. The shaft 22 is carried inbrackets or lugs 28 depending from the underside of a plate 29, slottedso that the jet housing may protrude therethrough and shaped so that itmay replace one or more of the blocks l0 and fit flush with the surfacethereof. One end of the hollow shaft 22 is closed and has mountedthereon a lever 30 carrying a counter balance weight 3i, and the otherend of said shaft is rotatably mounted within a hydraulic high pressuresupply pipe 32 provided with a packing gland 33.

The form of jet assembly described above is arranged to rotateautomatically into the .operative or inoperative position as thehydraulic high pressure supply is turned on or off, and the operation ofthe jet assembly utilises the reactive force created by the hydraulichigh pressure jet as it issues from the nozzle 24. The counter balanceweight 3i and lever 30 are arranged on the hollow shaft 22 so that whenthe hydraulic high pressure supply is turned off the weight 3| is in thelower of the two positions thereof shown in broken lines in Fig. 4 andthe flat surface 21a of the triangular jet housing 2| lies flush withthe blocks ill, the nozzle 24 being directed downwardly and to the leftas viewed in the drawing. This position is shown at A in Fig. 2.Rotation beyond this position is prevented by the stops 26 abuttingagainst the under side of plate 29. When the hydraulic high pressuresupply is turned on the reaction of the jet of water issuing from thenozzle 24 rotates the jet assembly and its hollow shaft 22 in thebearings 21 in an anti-clockwise direction through approximately furtherrotation being prevented by the abutment of the stop 26 against theplate 29. This position of the jet assembly is shown in Fig. 4 and at Bin Fig. 2.

A further form of jet assembly is shown in Figs. 11 and 12. In this formthe jet housing 34 is a box-like entity the upper face of which is at anangle corresponding to that of the blocks H) in which it is located. Thehousing has an internal conduit 35 one end of which is threaded toreceive the end of a pipe 36 which is telescopically mounted within ahydraulic high pressure supply pipe 31, the pipe 36 passing through apacking gland 38 fixed in the end of the pipe 31. At its other end theinternal conduit 35 of the jet housing 34 is threaded to receive thenozzle 39. The said housing has stops 40 extending from the under sidethereof so as to limit the distance the jet assembly protrudes above theblocks III in which it is arranged. Trunnions 4! on the pipe 36 areengaged by the arms of a bifurcated arm 42 made fast at its other end ona shaft 43 supported in a bracket 44 on the hopper base members 5 andextending through a bearing 45 mounted in the side wall 2 of the hopper.The end of the shaft 43 outside the hopper has fast thereon an arm 46engaging a nut 41 forming part of a screw and nut mechanism operated bya handle 48 secured on the screw 49.

. In operation the actuation of the screw and nut mechanism 41, 49 bythe handle 48 rocks the arm 42 on the shaft 43 and thereby raises orlowers the telescopically mounted pipe 36 and the jet assembly securedthereto. Upward movement of the assembly is limited by the stops 40abutting against the blocks ill and the retraction of the jet assemblybelow the level of the blocks in is prevented by a collar 50, fixed tothe pipe 36, which abuts against the neck ring 5| of the packing glandwhen the jet assembly is retracted.

Fig. 13 shows the above described jet assembly adapted for automaticactuation by the turning on or off of the hydraulic high pressuresupply. In this form the collar 50 supports the middle portion of alever 52 carrying a weight 53 at one end and pivotally mounted at theother end in a bracket 54 secured to the hopper'base I I.

When the hydraulic high pressure supply is turned on the pressuredifferential created between'the pipe 36 and pipe 31, due to the smallerdiameter of th former, raises the jet assembly into the operativeposition,- the action of the weighted arm returning it to itsretractedposition flush with blocks Ill when the hydraulic supply is turned ofi.

Figs. 14 and 15 show a streamlined construction of the jet housing 34,the stops 40 in this form being placed laterally of the housing.

I In Figs. 8, 9 and 10 a form of jet assembly is shown which is adaptedto be fitted in the side walls 2 of the hopper l. The jet assembly is ofsubstantially the same construction as that shown in Figs. 12 and 13 butthe end walls 55 and 56 of the jet housing 34 slope so that the housingmay be withdrawn diagonally within :the hollow metal wall block 51 inwhich it is mounted. The block 51 replaces a part of the refractorylining and metal facing in the side walls 2 of the hopper and is closedexteriorly of the hopper by a plate 58 formed with a tubular sleeve 59and an interior lug 60' integral there- 'with. The telescopic pipe 36extends through an opening in the lug 60 and the hydraulic high pressuresupply pipe 31 is mounted in the tubularsleeve 59. A helical spring BI'is mounted on the pipe 36 and abuts" at either end against the lug 50and the collar 50, normally holding the pipes 36 and 31 in the collapsedposition with the jet housing 34 flush with the wall of the block 5'!within the hopper I.

In the operation of this form, the turning on of the high pressurehydraulic supply causes the pipe 36 to be extended from the pipe 31against the action of the spring BI, the jet assembly protruding fromthe wall 2 into the hopper I and being retracted under the action of'the spring 6| when the high pressure hydraulic supply is turned off.

In the operation of the method according to the invention for removingand transport of furnace ash the ash 63 falling into the hopper I fromthe furnace is directed by the converging walls 2, 3 and 4 to form apile on the blocks l covering thebase 5. The blocks lfi are cooled bythe water circulating thereunder from the supply pipe 64 and thereforeproduce a partial cooling of the ash, the effect of which is to prevent.or minimise the fusing together of siliceous and other ash particles onthe blocks, such fused particles being resistant to erosion by the highpressure hydraulic jets. When it is desired to remove the ash from thehopper the arcuate gate I4 is opened and the high pressure hydraulicsupply to the jet assembly I8 in the wall of the gate casing I! isturned on. This jet assembly l8 directs a jet of water at high pressureagainst the front surface of the hot ash 63, the pressure of the jet andthe sudden cooling it produces causing erosion and disintegration of,the front portion of, the said pile of ash 63. The downward inclinationof the base causes the backwash of the jet to entrain the ash and conveyit clear of the hopper base 5 to fall inv the sluiceway I9 where theaqueous entrainment and re- -moval of the ash is assisted by one or morejets in the sluiceway. When the removal of the ash from the hopper basehas proceeded to the point where the foremost of the jet assemblies l8operating up the inclined base 5 are uncovered and cleared of ash thehigh pressure hydraulic supplythereto is turned on and the jetassemblies are automatically or manually brought into their operativeposition as hereinbefore' described. 'lhe e pw rd y dire ed ci s mb immmove a further quantity of ash, the backwash from the jets entrainingthe ash and carrying it down the inclined base to the sluiceway.

The operation of the aforesaid upwardly directed jets continues to erodeand distintegrate ash pile until the jet assembly operating down theinclined base 5 is freed of ash, and thisjet is then put into operation.The high pressure jet directed down the base 5 assists the entrainmentof the ash and its removal by the backwash of the upwardly operatingjets and clears the lower section of the base of ash.

As the face of the pile of ash recedes under the action of the highpressure jets further jet assemblies directed upwardly and downwardlyalong the inclined base 5 are successively brought into operation untilthe entire base of the hopper is substantially freed of ash deposit. Inorder to secure efllciency of operation of the jet assemblies theirspacing along the base 5 must be such that the distance betweensuccessive upwardly or downwardly directed jets is not greater than thedistance at which the jets are effective in eroding and disintegratingthe ash against which they are directed.

This distance will naturally vary according to the size of the nozzlesfitted in the jet assemblies and the pressure of water available for theoperation of the apparatus. The jet assemblies must also be so arrangedthat the jets therefrom operate over zones collectively including theentire width of the front surface of the pile of ash, so as to avoiduneroded islands of ash beingformed. These factors, as well as theresistance to erosion of the type of ash being dealt with, will decidethe disposition of the jet assemblies in any particular apparatus.

In addition to the jet assemblies arranged in the base 5 of the hopper,upwardly and downwardly directed jet assemblies provided in the sidewalls of the hopper may assist in the disintegration, entrainment andremoval of the ash, as shown in Figs. 8, 9 and 10.

The forms of construction of the jet assemblies shown in Figs. 11 to 15may be employed instead of the pivoting jet assemblies shown in Figs. 1,2, 4 and 5, the assemblies in either case being adapted for automaticoperation with the turning on or off of the high pressure hydraulicsupply, or for positive manual or mechanically assisted control. Forexample means may be provided for bringing one or more of the jetassemblies into or out of operation in any desired sequence by the useof remotely controlled solenoids orother operating mechanism, inconjunction with the control of the high pressure hydraulic supply.

operation and rotated or retracted to be flush with the base so as notto impede the entrained material removed by other jet assembliesoperating further up the inclined base. Thus the downwardly directedjets may be brought into use alternately with the upwardly directed jetsin succession from the front to the rear of the inclined base. n j y 9 Iclaim: 1. Apparatus for displacing and removing furnace ash or othersolid material from a trough shaped ash receiving hopper of greaterlength than breadth, the sides of which converge toward the base and thebase of which is inclined from one end to the other, that comprises apositively operated gate controlled frontal exit at the lower end ofsaid hopper, a series of rearwardly and a series of forwardly directedjet assemblies arranged in the surfaces of said hopper, a source of highpressure fluid supply connected to each of said jet assemblies, said jetassemblies being arranged in at least one line extending lengthwise ofsaid hopper, and at intervals along the length of said hopper notgreater than the effective operating range of said jets, so as toeffectively operate over the entire length of said hopper, means forselectively moving each of said jet assemblies into operating positionabove the surface of the hopper in which said jet is mounted and forselectively moving said jet assemblies to an inoperative position flushwith said hopper surface, and a sluiceway for receiving the materialdischarged from said frontal exit.

2. Apparatus as defined in claim 1 further characterized in that saidjet assemblies are mounted in the bottom surface of said hopper.

3. Apparatus as defined in claim 1 further characterized in that saidjet assemblies are mounted in the side surfaces of said hopper.

4. Apparatus according to claim 1 further characterized in that the jetassemblies are pivotally mounted in said hopper surfaces so as to lieflush with the interior surface when inoperative.

5. Apparatus as defined in claim 1 further characterized in that saidjet assemblies are retractably mounted in said surfaces so as to lieflush with the interior surface of the hopper when in inoperativeposition.

6. Apparatus as defined in claim 1 further characterized in that theparts of the jet assemblies that extend into the hopper when the jetassemblies are in operative position, are streamlined.

7. Apparatus as defined in claim 1 further characterized in that meansare provided for automatically moving the jet assemblies into operativeposition upon the supplying of fluid under pressure thereto and forautomatically retracting the jet assemblies into inoperative positionupon the cessation of fluid pressure supply.

8. Apparatus according to claim 1 further characterized in that meansare provided for automatically bringing the jet assemblies intooperating position upon the admission of fluid pressure thereto andgravity operated means are provided for retracting said jet assembliesinto inoperative position upon the cessation of fluid pressure supply.

9. Apparatus as defined in claim 1 further characterized in that thehopper base is formed of interlocking hollow metal blocks arranged sothat coolant may be circulated therethrough.

10. Apparatus as defined in claim 1 further characterized in that thehopper base is formed of a series of interlocking hollow metal blocksand the jet assemblies are shapedso that they each replace one or moreof said blocks.

11. Apparatus as defined in claim 1 further characterized in that anarcuate counterbalanced gate is provided at the hopper exit and thisgate is formed with recesses to permit drainage of fluid from saidhopper when said hopper is closed by said gate.

12. Apparatus as defined in claim 1 further characterized in that theexit from the hopper is enclosed by a housing in which is arranged a jetassembly directed so as to expel material entering said housing fromhopper.

13. Apparatus as defined in claim 1 further characterized in that eachof said assemblies is mounted rotatably on a hollow shaft through whichfluid under pressure can be supplied to the nozzle of said assembly,said assembly being rotatable into operative position by the reaction ofthe fluid issuing from its nozzle and returnable to inoperative positionby gravitational means.

14. Apparatus according to claim 1 wherein said jet assemblies aremounted on pipes slidably mounted in one end of high pressure hydraulicconduits so as, on the admission of fluid under pressure thereto, to beraised into the operative position, the retraction of said assemblies"to the inoperative position being effected by a counterbalance weightmounted thereon.

15. Apparatus according to claim 1 wherein the walls of said hopper areprovided with a lining of refractory material and the lower part of saidwalls is faced with metal.

16. Apparatus according to claim 1 wherein stops are provided on saidjet assemblies to limit the movement of said jet assemblies into theoperative or inoperative positions thereof.

ARTHUR WYLDE DANIELS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 439,961 Lewis Nov. 4, 18901,772,452 Allen .Aug. 12, 1930 1,775,264 Allen Sept. 9, 1930 1,818,967Allen Aug. 18, 1931 1,905,570 Rome Apr. 25, 1933

